In general, an X-ray tube assembly is used in a medical diagnosis system, an industrial diagnosis system or the like. The X-ray tube assembly comprises an X-ray tube which radiates X-rays, etc. The X-ray tube comprises a cathode including a focusing electrode and a filament which emits electrons, an anode with which the electrons emitted from the filament collide to radiate X-rays, and an envelope which accommodates the cathode and the anode. Electrons traveling from the cathode toward the anode are accelerated by the potential difference between the cathode and the anode, and are focused by the focusing electrode.
The focusing electrode, terminal assemblies and pin assemblies are attached to an insulating member, and electrically insulated from each other by the insulating member. The terminal assemblies support the filament. The pin assemblies are also attached to the envelope. Metallic thin wires (or metallic foil bands) are welded to the terminal assemblies and the pin assemblies, thus electrically connecting the terminal assemblies and the pin assemblies to each other. A current and a voltage are supplied and applied to the filament through the pin assemblies, the metallic thin wires and the terminal assemblies.